linuxPackages.virtualboxGuestAdditions: don't install VBoxOGL for now

It seems to be broken upstream too, and fixing it is far down the
priority list:
https://www.virtualbox.org/pipermail/vbox-dev/2017-June/014561.html
Additionally, 3d support seems to rely on VBoxOGL.so being symlinked
from libGL.so (which we can't), and Oracle doesn't plan on supporting
libglvnd either. (#18457)